Single Origins vs. Blends

Single-origin chocolate are those whose beans come from one origin. The meaning of the word origin, however, is quite subjective. To one manufacturer, having "one origin" could mean that all the beans are form one area or region, while another manufacturer might define that same term to mean the beans all come from the same, single crop. Sometimes the word varietal is used in place of origin.
Blends are exactly that - a mix of different beans from different regions and different crops. Blends can contain any number of differences and are not relegated to specific numbers of beans.